Jewelry rope chains are necklace chains, or the like, made from a helicoid configuration of number of individual ring shaped annular links, which links are intertwined to form a double helix helicoid resembling a rope, and thus these chains are known as rope chains. The prior art includes a diamond cut solid annular rope chain, in which solid annular links are given a quality of sparkle by cutting and shearing away flat facets from the curved solid annual toroid links, leaving flat surfaces for light to reflect off of. Before discussing hollow, as opposed to solid, faceted chains, a review of jewelry chains in general is hereby noted.
In general, jewelry rope chains are made of precious or any other metals, and can be made of solid links, or of hollow links. The former are known as "solid rope chains" and the latter are known as "hollow rope chains".
As noted above, in order to add the sparkling quality to the solid rope chains, these solid rope chains are subject to a process known as "diamond cutting", which consists using sharp diamond cutting knives to cut off segments of the chain (usually known as "facetting"), in any given number of flat facets, and making use of various methods for cutting into the surface of the solid annular links so that these flat facets which will reflect light in various angles, making the particular diamond cut rope chain shinier than a non-diamond-cut chain. Therefore, these chains are known as "solid diamond cut rope chains".
However, the manufacture of solid diamond cut rope chains remains very expensive, because during the last two decades, the world of the jewelry business has suffered two economic misfortunes:
i. The world price for gold has increased about ten-fold, from about US$35 a Troy Ounce, going to a peak of about US$850 a Troy ounce, through today's average price of about US$350 per Troy ounce; and, PA1 ii. The average consumer acquisitive capacity has suffered a decline. Even though world-wide this decline is hard to quantify because of the great fluctuations that most economies have suffered and continue to do so. However, such a decline can be felt by the average individual jewelry manufacturer in most developed countries. PA1 1. With respect to closed links, this is where each individual annular link is soldered in the closing, thus not allowing the intertwined links to come apart. The closings of the annular links are oriented in the same direction. PA1 2. where each annular link has an opening or gap slightly larger than the wire diameter from which the said annular links are made, this permits one of said annular links forming the rope chain to pass through the gap of another of the annular links forming the rope chain. The orientation of the gap of the links is alternating, so that when the gap of two angularly intertwined and laid adjacent links is thereto, said second annular link is oriented so that its said gap is 180 degrees removed from the orientation of the first link gap. Two adjacent links with gaps 180 degrees orientation are soldered together, intermittently at the external periphery.
These requirements have prompted the world's jewelry manufacturers in general, and the jewelry chain manufacturers in particular for a quest to create products that "look-alike" aesthetically to the heavier product of a solid gold chain, but are much lighter in weight. This look-alike simulated effect is achieved by using a lesser amount of precious material content in the jewelry objects being manufactured, without altering the appearance and "look" of such a heavier jewelry object, such as a solid gold chain.
Therefore, in the jewelry rope chain industry, many efforts have been made so that a hollow chain will exhibit the same aesthetic look of a solid rope chain, such that a reduction can be effected in the weight of the chain, thus reducing its cost. This has been achieved until now in various ways, such as for example, by manufacturing the annular links of a smaller diameter, by altering the size and thickness of annular links that conform a determined length of chain, and in trying to reduce the weight of a chain of the same length and similar appearance.
The largest breakthrough in the look-alike but cost-less quest was achieved when the rope chain industry created the aforementioned hollow rope chain, which in some cases reduce the original weight of a look-alike solid rope chain up to 50% and even 60%.
Such hollow rope chains are jewelry rope chains manufactured out of hollow annular links. A variety of weaving techniques may be used, with a variety of the number of links being intertwined. This is true whether the links be an odd or an even number of links. Moreover, the basic element of a hollow rope chain is an annular link that has a void in its inner side.
Hollow chains must meet certain qualitative manufacturing standards.
A well manufactured jewelry rope chain is one whose links are scratch-less, uniform in size and tightly woven. This is achieved in the solid rope chain by using clean, precise methods of link manufacturing, a very tight weaving process, which in the case of a hand-made rope chain, demands an extra process called "tightening", entailing bunching the woven links as many as possible in a given length without bending the links out of its circular form. Care is taken also, in the soldering process, so as to "straighten" any misplaced links before applying the solder.
Because of the fact that hollow rope chains are in fact made from hollow links, hollow jewelry chains are more delicate than their look-alike solid links. As a result, the hollow links, and the hollow chain that is derived from such links is liable to be bent, bunched, warped or otherwise deformed before, during and/or after the manufacturing process.
In addition, because of the fact that a hollow link is manufactured from a very thin plate, the plate itself has to be perfectly made in respect to its thickness and width in order that a strong link be made out of it. The largest problem encountered in the manufacturing of a hollow rope chain is the fact that it can hardly be "tightened" because of its delicate structure. This gives place to a certain "looseness" in the finished hollow rope chain, which will not be encountered in a well made solid rope chain.
Before discussing the imprinting of flattened facets upon hollow rope chain links, it is necessary to describe the manufacture of linked rope chains in general.
Specifically, solid and hollow jewelry rope chains are made by machines and by hand. When a plurality of links are intertwined to form a double helix helicoid chain the rope chain is produced. Each link in the rope chain is generally curved, annular and, curved again in a C-shape. The links are referred to as "annular" since the these ring shaped links wrap around each other. The jewelry industry uses two types of annular links in the art of rope chain manufacturing:
Jewelry rope chain made of these closed links are generally referred to as "machine made rope chains", and the rope chain made of open links, whether they are made by machines or by hand are called "hand made rope chains".
Machine made rope chains can have any number of intertwined links odd or even number equal or greater than 2.
Hand made rope chains can have only odd number of intertwined links equal or greater then 3.
The size of the inner annular diameter of a typical annular, ring shaped link for the hand made rope chain in the prior art of the rope chain has been a slightly over 3:1 ratio (e.g. 3.2-3.7:1) to the wire diameter of the wire from which the solid annular links are made of.
Having discussed the formation of rope chains in general, it is necessary to discuss the relevance of the annular links to hollow chains in general.
As noted before, the increasing gold price of the last two decades promoted a competition between the chain manufacturers and chain machine manufacturers to create more lighter and lighter chains having the same aesthetic appearance as a heavier chain but less gold content.
To achieve the above, the following constraints are noted.
With the higher the number of annular links being intertwined, whether the rope chain is a machine made rope or a hand made rope chain, the thinner must be the wire diameter from which the annular links are made. Furthermore, the thinner the wire diameter from which the annular links are made for the same outside diameter of chain and the same unit length of chain, will result in a lighter chain.
Also the basic element of the hollow rope chain, namely the hollow link, while it is being formed, the tubular link requires (due to the very thin wall) the introduction of a supporting wire introduced during fabrication to allow the forming of the link. In the absence of the introduced core, the thin wall would fracture.
With respect to the introduction of a supporting core, it must be noted that there are two types of hollow tubes, each requiring a separate type of inner support during formation. One type is known as a "seamless" tubular link, which is a basically toroid donut shaped link with an uninterrupted, continuous surface. After finishing assembling the chain made of the "seamless" precious metal tubing, with a non-precious metal core, the nonprecious metal core has to be removed by dissolving it in concentrated acid. Such an operation is very slow, due to limited surface contact between the acid and the metal core. With this technology there are a very limited quantity of chains made.
The second type of tubular link is a "seamed" tubular link,also generally toroid donut shaped in configuration, but which presents an circumferential gap or "seam" on the inner circumferential surface, similar in shape to an automobile tire with a gapped seam on its inner circumference.
A more simple less complicated, more efficient way is being widely used in the art of chain manufacturing with the aforementioned "seamed" tubular link, which has the inner circumferential gap as in an automobile tire configuration. The seamed tubular links are formed when a sheet metal plate of 0.002-0.004" together with a solid non precious metal core is drawn through a round die so that the sheet metal of precious metal forms an open tube with a non precious metal core. The precious sheet metal is wrapped around the non precious metal wire allowing an opening of 15%-20% of the median circle of the circular cross-sectional ring formed.
The opening along the formed link allows the access of the acid to the non precious metal core on the entire length of the link thus accelerating the dissolving of the non precious metal core. However, the thus formed hollow links are very thin, and subject to fracture. Therefore they cannot be sheared and cut, to create flat, sparkling facets, as is done with solid link rope chains.
In contrast, as noted before, diamond cutting of solid link chains is a well known finishing step in the manufacturing of jewelry chains. By shearing or cutting, and removing a very thin layer of metal (0.002-0.004") by special diamond cutting tool, a very highly reflective surface is created, with a shine which surpasses other shines made by any other method.
Diamond cutting of solid links of solid rope chains is accomplished with a deep cut being used, so that from the round rope chain a four or six faceted square or hexagon shaped in cross-section results. This way the diamond cut flat surface created in the solid chain gives an enhanced sparkling look to the chain.
Until now, due to the very thin wall of the hollow chains and especially hollow rope chains, diamond cutting as aforesaid was impossible to envision.
For example, to achieve a square or hexagon in cross-section like chain, the depth of the cut would have to be greater than the wall thickness of the annular tube the hollow rope chain is made of.
In view of the aforesaid complexities of jewelry rope chain manufacture, various methods have been patented to improve the rope chain manufacturing technology.
Japanese Patent Document 0260644 dated Oct. 27, 1988 of Masuda described an annular link wherein selected portions of a surface of the link are plated and then removed by grinding. German Patent No. 2724695 of Lange concerns hollow links which are square in cross-section and which have a portion of the walls removed.
U.S. Pat. No. 4,716,750 of Tizzi discloses rotary swaging and annealing, repeated in sequence, to produce hollow articles with various tubular cross-sections. U.S. Pat. No. 4,754,535 of Valtiero discloses the use of ice as a packing material support for surface alteration of thin continuous stock. U.S. Pat. Nos. 2,424,924 of Chernow and 2,711,069 of Ambrust describe methods of producing ornamental facets on solid wire chain links through grinding operations. U.S. Pat. Nos. 3,083,002 of Lacey and 4,268,946 of Eisenberg disclose the use of a solidifying material, such as ice, as a chuck to hold jewelry workpieces in place. Both of these patents are directed towards cutting of thin metal workpieces, the Eisenberg '946 patent particularly directed toward cutting tubular members.
U.S. Pat. Nos. 2,895,290 of Devonshire, 3,410,085 of Sheth, 4,679,391 of Tizzi and 4,682,467 of Waltmeyer disclose stamping impressions into solid chain links. The '391 patent is directed particularly toward jewelry.
U.S. Pat. No. 4,681,664 of Eberle discloses the altering or reinforcing of hollow thin walled jewelry articles by electro-forming at stress points (such as at joints to increase their strength). U.S. Pat. No. 4,996,835 of Rozenwasser discloses the use of both solid or hollow links in jewelry rope chains, and German U.S. Pat. No. 2,428,647 appears to disclose the use of a solidifying agent as a chuck to hold workpieces.
Other related patents include U.S. Pat. No. 4,986,067 of Caccialupi, U.S. Pat. No. 4,091,510 of Kinzel, U.S. Pat. No. 3,983,716 of Kuhn and U.S. Pat. No. 4,635,324 of Hoerkens. Further foreign patents include Brazilian Patent No. 8802156 of Friedrich, British Patent No. 2036537 of Leshik, German Patent No. 2448897 of Schwerdfeger, German Patent No. 2445662 of Schuler, German Patent No. 3981920 of Eberle, French Patent No. 2628301 of Jacqueson and French Patent No. 2611451 of Vessigot.
The aforementioned patents do not describe a hollow rope chain bearing generally flat, reflective facet surfaces to increase visual sparkling effect while maintaining the structural integrity of the annular links of the hollow rope chain.
The aforementioned patents either disclose making hollow tubings, such as disclosed in the Tizzi '750 patent, or the surface alteration of solid links, such as disclosed in Chernow '924, Ambrust '069 and Tizzi '750 patents.
The Eberle '664 patent concerns the altering of hollow jewelry articles by electro forming the hollow articles at stress points but does not describe a method of incrementally deforming curved hollow links to produce a flattened facet surface.
The Valtiero '535 patent discloses altering flat, thin metal strips by applying a supporting base, such as ice, and then impressing the strip with pre-coined impressions.
However, the Eberle '664 and Valtiero '535 do not describe the surface deformation of the curved surface of an annular ring shaped jewelry link by the application of incremental pressure upon the curved wall surface, thereby deforming the curved outer wall inward until a flattened surface appears.